Hanging upside down is just what an arboreal gecko does. They live in trees and shrubs and they rest in positions that look wrong to us. On its own it is nothing.
The glass is the part worth acting on. Floppy tail is associated with geckos spending long stretches resting head-down on bare smooth glass, which loads the pelvis and tail base, and in bad cases has been linked to deformity there. Your enclosure has two vertical cork rounds, which is to say it has almost nowhere to lie down.